[Tex/LaTex] How to define colors in style file (lstlang0.sty)

colorlistings

Per the listings package documentation, I have a file lstlang0.sty in the same directory as my .tex file (well, .lyx file) which defines a new language. I used to have this language definition in my preamble but since it's being used in at least four documents now, I am very motivated to maintain it as a separate style file.

I've defined colors to provide syntax highlighting and that's where things get hung up.

This block was previously in my preamble and now resides in my lstlang0.sty file. Note it used lstdefinelanguage in the preamble (no '@'). Also, I've snipped out most of the keywords for convenience.

\lst@definelanguage[CR]{Basic}{%
  basicstyle={\ttfamily\footnotesize},%
  sensitive=false,%
  upquote=true,%
  string=[bd][\color{crbString}]{"},%
  showstringspaces=false,%
  morekeywords=[1]{Const, Public, <snip> ...},%
  keywordstyle={[1]{\color{crbKeyword}}},%
  otherkeywords={=, /, *, +, -, *=, /=, +=, -=, <<, >>, ^, <, >},%
  morekeywords=[2]{=, /, *, +, -, *=, /=, +=, -=, <<, >>, ^, <, >},%
  keywordstyle={[2]{\color{crbKeyword}}},%
  morecomment={[l][\color{crbComment}\ttfamily\itshape]{'}}%
}
\endinput

Things compile correctly so long as the colors (crbKeyword, crbString, crbComment) are defined in the preamble. Attempting to define them in the style file like so:

\definecolor{crbString}{RGB}{255,0,255}
\definecolor{crbKeyword}{RGB}{0,0,255}
\definecolor{crbComment}{RGB}{0,128,128}
\lst@definelanguage[CR]{Basic}{%
  ...

gives me a long list of errors:

LaTeX Error: Undefined color 'crbKeyword'.
LaTeX Error: Undefined color 'crbKeyword'.
LaTeX Error: Undefined color 'crbComment'.
...

I tried adding \RequirePackage{color} above the color definitions in the style file and LaTeX first complains "Can only be used in preamble" followed by the same undefined color errors. Encasing the color definitions with \AtBeginDocument{..} produced the same results.

What do I need to change to get the color definitions into lstlang0.sty?

I did notice no other listings language definitions include syntax coloring. Is there any (technical) reason?

Best Answer

The language definition files, despite using the file extension .sty aren't regular packages, so you can't put anything inside them other than \lst@definelanguage commands. Instead, for other listings related LaTeX code, like your colour definitions, you should use the listings.cfg file.

So put the colour definitions there, and everything will work as you expect.

If you only want these definitions to work for a particular language, (in your case Basic), you can put them into a file named listings-<language>.prf and then in your lstlocal.cfg file you add \input{listings-<language>.prf}. Both files can be placed in a listings directory within your local texmf directory.

So to be more explicit for your particular example, you can create the following files:

listings-basic.prf

\definecolor{crbString}{RGB}{255,0,255}
\definecolor{crbKeyword}{RGB}{0,0,255}
\definecolor{crbComment}{RGB}{0,128,128}
\endinput

lstlocal.cfg

\input{listings-basic.prf}

Or simply put the definitions directly into lstlocal.cfg and they will be available for any language definitions that use them.

Related Solutions

[Tex/LaTex] listings: General settings for a language seem to be overwritten/not respected

You seem to think that \lstset sets parameters for one specified language, i.e., the language given within \lstset. That is not how it works. Your code first sets the default language for all listings of your document to TeX, then it sets it to R, and so on. Similarly, it sets three default keywords for all listings of your document (if, else, function), but when you typeset your R listing, the keyword list that belongs to R overwrites the default keyword list.

What you actually want is probably best achived with styles, or you define a new language based on R, or a new dialect of R. Let's try with styles:

\documentclass{scrartcl}

\usepackage[T1]{fontenc}
\usepackage[american]{babel}
\usepackage{xcolor}
\usepackage{fancyvrb}
\usepackage{listings}

% this style should be active for all lstlistings environments
\lstdefinestyle{all}{
  basicstyle=\ttfamily\small,
  frame=lrtb, framerule=1pt, framexleftmargin=1pt,
  showstringspaces=false
}

% this style should be active (additionally to "all") for "input" lstlistings environments
\lstdefinestyle{input}{
  commentstyle=\itshape\color{red},
  keywordstyle=\color{blue}
}

\lstdefinestyle{newLaTeXsettings}{
  style=all,
  keywords={},
  otherkeywords={}
}


% listings settings for R (should hold for all R listings in general)
\lstdefinestyle{newRsettings}{
  style=all,
  literate={<-}{{$\leftarrow$}}2,% this is respected
  keywords={if, else, function},% this is not respected
  otherkeywords={}
}

\begin{document}

\begin{lstlisting}[language={[LaTeX]TeX}, style=input, style=newLaTeXsettings]
\begin{enumerate}
\item foo % bar
\end{enumerate}
\end{lstlisting}

\begin{lstlisting}[language=R, style=input, style=newRsettings]
x <- 4
s <- lapply(1:10, function(z) z+x)
k <- sapply(1:10, function(z) z+2*x) # other case
\end{lstlisting}

\end{document}

[Tex/LaTex] Context dependent keyword color (listings). Question regarding (ab)using “otherkeywords”

In the world of listings, there are mainly three kinds of characters: letter, digit, and other. (It is not pronounce or adjective, but a class named o-t-h-e-r literally.) The manual says that all keywords (should) consist of a letter followed by alpha-numeric characters. That is to say that ab, a2 are good keywords and that 12, 1b, 1?, a?, !b, !2, and !? are not keywords.

So, what makes others so special? An answer is that others are used to separate tokens. In your example, we recognize print as a method/function because it is separated by ./:: and (). Otherwise if . and : were letters we can only see two tokens, namely my_class.print() and my_class::print.

In this example, only the second bar is bold because listings sets alsoletter={.}, for [5.0]Lua.

\begin{lstlisting}[language={[5.0]Lua},morekeywords={bar}]
    foo.bar
    foo:bar
\end{lstlisting}

But sometimes we really need to color such symbols. So listings allows one to write otherkeywords={=>}. Notice that the second bar is still bold --- because listings still regards = as other.

\begin{lstlisting}[language={Haskell},morekeywords={bar}]
    foo=>bar
    foo<=bar
\end{lstlisting}

But otherkeywords does not support class number. In your example,

classoffset=2,
keywordstyle=\hakuna,
morekeywords={matata},

is equivalent to keywordstyle=[2]\hakuna, meaning applying \hakuna for all second class keyword, and morekeywords=[2]{matata}, meaning adding matata as a second class keyword.

However, as in your question 1, there is no otherkeywords=[2] syntax.

For question 2 it is hard to tell why it works. The remaining is my guess: writing morekeywords=[3]{Aal::Izz.Well} will make listings add Aal::Izz.Well as a third class key word. But listings will not see this keyword when parsing your code because, as I explained, others separates tokens. However, otherkeywords={Aal::Izz.Well} forces listings take a look, after it reads Aal, at : and do further checks.

You may try something like:

\lstnewenvironment{print}{%
    \lstset{style=PRETTYPRINT}
    \tracingmacros1
    \lstset{morekeywords=[1]{Aal::Izz.Well}}
    \tracingmacros0
    \lstset{otherkeywords={Aal::Izz.Well}}
}{}

and found that even otherkeywords add the keyword to the first class. The latter appear to be in the third class. (guess why~~)

Best Answer

Related Solutions

[Tex/LaTex] listings: General settings for a language seem to be overwritten/not respected

[Tex/LaTex] Context dependent keyword color (listings). Question regarding (ab)using “otherkeywords”

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